Large Underground Xenon dark matter experiment/LHC LSP neutr

[kodama]

Large Underground Xenon dark matter experiment and LHC have reported a null result on searches for dark matter, with new bounds.

What are the implication of these new bounds on neutralinos and LSP?

 

[Buzz Bloom]

Hi kodama:
Since there been no other replies to your question, I will try to make a useful comment, based on my non-expert interpretation of articles I found by a brief internet search.

Regarding the LSP.
https://en.wikipedia.org/wiki/Lightest_Supersymmetric_Particle
This article says:
The LSP of supersymmetric models is a dark matter candidate and is a Weakly interacting massive particle (WIMP).
The article
http://www.quantumdiaries.org/2014/...-with-the-large-underground-xenon-experiment/
says no WIMPs were found. Therefore one can conclude that no LSPs were found, and that there is a significant likelihood that they do not exist as a kind of DM.

Re neutralinos,
https://en.wikipedia.org/wiki/Neutralino
seems to be saying that neutralinos are not WIMPs. Therefore it seems reasonable to conclude that the XENON based experiment says nothing about the possibility that neutralinos might exist as a kind of DM.

Regards,
Buzz

 

[mfb]

Therefore one can conclude that no LSPs were found, and that there is a significant likelihood that they do not exist as a kind of DM.

Where would such a significant likelihood come from?
The exclusion limits keep improving, but you can always reduce couplings to make the particles invisible to current experiments.

 

[kodama]

Where would such a significant likelihood come from?
The exclusion limits keep improving, but you can always reduce couplings to make the particles invisible to current experiments.

what about LHC? no neutralinos detected or produced at 8TEV energies.

 

[mfb]

My post applies to both LHC and direct dark matter searches like XENON.

 

[kodama]

My post applies to both LHC and direct dark matter searches like XENON.

lhc is based on finding missing energy. none found.

 

[MathematicalPhysicist]

Large Underground Xenon dark matter experiment and LHC have reported a null result on searches for dark matter, with new bounds.

What are the implication of these new bounds on neutralinos and LSP?

I would think that if dark matter isn't found then perhaps we should be tweaking Newton's laws; I mean besides MOND which is only modifying Newton's laws, perhaps a serious shakeup in the fundamentals of physics is due.

 

[mfb]

lhc is based on finding missing energy. none found.

Missing energy is one part of the signature of possible dark matter-like particles, but the searches are more complex than that.

No dark matter found so far: sure. It would be impossible to miss such a discovery.

I would think that if dark matter isn't found then perhaps we should be tweaking Newton's laws; I mean besides MOND which is only modifying Newton's laws, perhaps a serious shakeup in the fundamentals of physics is due.

Every new theory has to satify constraints from thousands of measurements. That is a huge challenge. If you just start making up hypotheses, they will fail to agree with many of those experimental results.

 

[kodama]

Missing energy is one part of the signature of possible dark matter-like particles, but the searches are more complex than that.

No dark matter found so far: sure. It would be impossible to miss such a discovery.Every new theory has to satify constraints from thousands of measurements. That is a huge challenge. If you just start making up hypotheses, they will fail to agree with many of those experimental results.

isnan===

Missing energy is one part of the signature of possible dark matter-like particles, but the searches are more complex than that.

No dark matter found so far: sure. It would be impossible to miss such a discovery.Every new theory has to satify constraints from thousands of measurements. That is a huge challenge. If you just start making up hypotheses, they will fail to agree with many of those experimental results.

i can understand how changing coupling constants can evade bounds of lux, but lhc?

isn't 8 tev enough to create 10-100 gev neutralinos, detected by missing energy?

 

[mfb]

Smaller coupling constants reduce the number of events. If the number is small enough, those events get swamped by background events

 

[Buzz Bloom]

Where would such a significant likelihood come from?

Hi @mfb:

Thank you for pointing out my careless phraseology.

Perhaps I should have said:

"there is a significant possibility that they do not exist as a kind of DM.​

Is this an acceptable statement?

Regards,
Buzz

 

[mfb]

Well, something particle-like is quite likely based on cosmological observations, but it does not have to be a supersymmetric particle, sure. Supersymmetry does not have to exist at all.

 

[kodama]

Well, something particle-like is quite likely based on cosmological observations, but it does not have to be a supersymmetric particle, sure. Supersymmetry does not have to exist at all.

what about scalar dark matter? more wave like than particle

 

[mfb]

In particle physics such a classification does not make sense. Both "waves" and "particles" are described with the same framework of quantum field theory.

 

[kodama]

In particle physics such a classification does not make sense. Both "waves" and "particles" are described with the same framework of quantum field theory.

how adjustable is the coupling for neutralinos and other WIMPS?

 

[mfb]

I'm not a theoretician, but in general the phase spaces are usually larger than the exclusion limits experiments can set.

 

[kodama]

I'm not a theoretician, but in general the phase spaces are usually larger than the exclusion limits experiments can set.

are you HEP? i ask bc i wonder if ultra-light scalar field dark matter is perhaps the best theory, esp with current exclusion limits from LUX.

i.e no WIMPS, no DM from 1EV-10TEV

DM is ultra-light scalar field dark matter. no cuspy halos. perhaps axions as well around 10 kuev

how would the SM change if they add ultra-light scalar field dark matter ?